CD4 and HIV infectious disease: There are several factors that could account for contrasting observations on the role of 5′-LTR methylation on HIV latency, including the length of HIV infection, ART regimen used, time on ART, cell type studied, CD4+ T cell subpopulation composition, rate of replacement of latently infected CD4+ T cells, proportion of defective proviruses, and HIV integration sites [16, 17, 19].